Body Ownership, Schizophrenia, and the Importance of Exercise

Psychologists use a procedure called “The Rubber Hand Illusion” to challenge an individual’s sense of body ownership. A recently published study showed that schizophrenics – who already exhibit a weak sense of self – experienced the illusion to a greater degree than healthy controls.

Other research suggests that focused physical exercise can help improve body ownership and thereby alleviate some symptoms of schizophrenia.

Body Ownership and “The Rubber Hand Illusion”

In the “The Rubber Hand Illusion,” participants begin to perceive a rubber hand as if it was a part of their own body. The experiment is fairly simple, but it can have some wild effects.

Researchers hide one of your hands behind a small sheet and then put a rubber hand into view. They then stroke a paintbrush along both your real hand (the one that’s hidden), and the rubber one.

What happens among two thirds of healthy participants is that they begin to perceive that the sensations of the paintbrush are actually coming from the rubber hand, not their real one. When participants are then asked to close their eyes and point toward their real hand, many will point closer toward the rubber one instead.

The “Rubber Hand Illusion” is a play on vision, touch, and body posture (proprioception). Often the stronger the effect, the less someone has a true sense of “body ownership.” To get a better idea on how the experiment works, you can check out a video of the illusion below:

Schizophrenia and “The Rubber Hand Illusion”

Those with schizophrenia are already known to have a poor concept of self, a big part of which includes their sense of “body ownership.”

In a recently reported study, schizophrenics were shown to have a much more heightened effect when undergoing this “Rubber Hand Illusion.” When asked to point toward their real hand, schizophrenics pointed significantly closer to the rubber one than their real one when compared to healthy controls. One participant in the study even reported floating completely above their body for about 15 minutes – a very rare case of an “out of body experience” (OBE) being spontaneously produced in the laboratory.

These findings fit perfectly with the already existing theory that those with schizophrenia have a weaker sense of self and body ownership.

The Importance of Physical Exercise for Schizophrenics

Previous research has shown that physical exercise can help reduce symptoms of schizophrenia (see here and here).

This is because physical exercise, especially focused activities like yoga and dance, can help improve an individual’s body awareness and body ownership.

Of course, this doesn’t mean exercise is a cure-all for schizophrenia, but there is some strong evidence that it is a supplementary treatment worth trying out. Even just 20 minutes a day for 3 weeks can lead to some noticeable improvements.